Struct procfs::process::Process

pub struct Process {
    pub pid: i32,
    /* private fields */
}

Represents a process in /proc/<pid>.

Note The Process struct holds an open file descriptor to its /proc/<pid> directory. This makes it possible to construct a Process object and then later call the various methods on it without a risk of inadvertently getting information from the wrong process (due to PID reuse).

However the downside is that holding a lot of Process objects might cause the process to run out of file descriptors.

For use cases that don’t involve holding a lot of Process objects, no special handler is needed. But if you do hold a lot of these objects (for example if you’re writing a ps or top -like program), you’ll likely want to gather all of the necessary info from Process object into a new struct and then drop the Process object

Fields

pid: i32

Implementations

impl Process

pub fn limits(&self) -> ProcResult<Limits>

Return the limits for this process

impl Process

pub fn mountstats(&self) -> ProcResult<Vec<MountStat>>

Returns the MountStat data for this processes mount namespace.

pub fn mountinfo(&self) -> ProcResult<Vec<MountInfo>>

Returns info about the mountpoints in this this process’s mount namespace

This data is taken from the /proc/[pid]/mountinfo file

(Since Linux 2.6.26)

impl Process

pub fn namespaces(&self) -> ProcResult<HashMap<OsString, Namespace>>

Describes namespaces to which the process with the corresponding PID belongs. Doc reference: https://man7.org/linux/man-pages/man7/namespaces.7.html The namespace type is the key for the HashMap, i.e ‘net’, ‘user’, etc.

impl Process

Methods for constructing a new Process object.

pub fn new(pid: i32) -> ProcResult<Process>

Returns a Process based on a specified PID.

This can fail if the process doesn’t exist, or if you don’t have permission to access it.

pub fn new_with_root(root: PathBuf) -> ProcResult<Process>

Returns a Process based on a specified /proc/<pid> path.

pub fn myself() -> ProcResult<Process>

Returns a Process for the currently running process.

This is done by using the /proc/self symlink

impl Process

pub fn cmdline(&self) -> ProcResult<Vec<String>>

Returns the complete command line for the process, unless the process is a zombie.

pub fn pid(&self) -> i32

Returns the process ID for this process, if the process was created from an ID. Otherwise use stat().pid.

pub fn is_alive(&self) -> bool

Is this process still alive?

pub fn uid(&self) -> ProcResult<u32>

What user owns this process?

pub fn cwd(&self) -> ProcResult<PathBuf>

Retrieves current working directory of the process by dereferencing /proc/<pid>/cwd symbolic link.

This method has the following caveats:

• if the pathname has been unlinked, the symbolic link will contain the string “ (deleted)“ appended to the original pathname

• in a multithreaded process, the contents of this symbolic link are not available if the main thread has already terminated (typically by calling pthread_exit(3))

• permission to dereference or read this symbolic link is governed by a ptrace(2) access mode PTRACE_MODE_READ_FSCREDS check

pub fn root(&self) -> ProcResult<PathBuf>

Retrieves current root directory of the process by dereferencing /proc/<pid>/root symbolic link.

This method has the following caveats:

• if the pathname has been unlinked, the symbolic link will contain the string “ (deleted)“ appended to the original pathname

• in a multithreaded process, the contents of this symbolic link are not available if the main thread has already terminated (typically by calling pthread_exit(3))

• permission to dereference or read this symbolic link is governed by a ptrace(2) access mode PTRACE_MODE_READ_FSCREDS check

pub fn environ(&self) -> ProcResult<HashMap<OsString, OsString>>

Gets the current environment for the process. This is done by reading the /proc/pid/environ file.

pub fn exe(&self) -> ProcResult<PathBuf>

Retrieves the actual path of the executed command by dereferencing /proc/<pid>/exe symbolic link.

This method has the following caveats:

• if the pathname has been unlinked, the symbolic link will contain the string “ (deleted)“ appended to the original pathname

• in a multithreaded process, the contents of this symbolic link are not available if the main thread has already terminated (typically by calling pthread_exit(3))

• permission to dereference or read this symbolic link is governed by a ptrace(2) access mode PTRACE_MODE_READ_FSCREDS check

pub fn io(&self) -> ProcResult<Io>

Return the Io stats for this process, based on the /proc/pid/io file.

(since kernel 2.6.20)

pub fn maps(&self) -> ProcResult<Vec<MemoryMap>>

Return a list of the currently mapped memory regions and their access permissions, based on the /proc/pid/maps file.

pub fn smaps(&self) -> ProcResult<Vec<(MemoryMap, MemoryMapData)>>

Returns a list of currently mapped memory regions and verbose information about them, such as memory consumption per mapping, based on the /proc/pid/smaps file.

(since Linux 2.6.14 and requires CONFIG_PROG_PAGE_MONITOR)

pub fn pagemap(&self) -> ProcResult<PageMap>

Returns a struct that can be used to access information in the /proc/pid/pagemap file.

pub fn fd_count(&self) -> ProcResult<usize>

Gets the number of open file descriptors for a process

Calling this function is more efficient than calling fd().unwrap().count()

pub fn fd(&self) -> ProcResult<FDsIter>

Gets a iterator of open file descriptors for a process

pub fn fd_from_fd(&self, fd: i32) -> ProcResult<FDInfo>

pub fn coredump_filter(&self) -> ProcResult<Option<CoredumpFlags>>

Lists which memory segments are written to the core dump in the event that a core dump is performed.

By default, the following bits are set: 0, 1, 4 (if the CONFIG_CORE_DUMP_DEFAULT_ELF_HEADERS kernel configuration option is enabled), and 5. This default can be modified at boot time using the core dump_filter boot option.

This function will return Err(ProcError::NotFound) if the coredump_filter file can’t be found. If it returns Ok(None) then the process has no coredump_filter

pub fn autogroup(&self) -> ProcResult<String>

Gets the process’s autogroup membership

(since Linux 2.6.38 and requires CONFIG_SCHED_AUTOGROUP)

pub fn auxv(&self) -> ProcResult<HashMap<u64, u64>>

Get the process’s auxiliary vector

(since 2.6.0-test7)

pub fn wchan(&self) -> ProcResult<String>

Gets the symbolic name corresponding to the location in the kernel where the process is sleeping.

(since Linux 2.6.0)

pub fn status(&self) -> ProcResult<Status>

Return the Status for this process, based on the /proc/[pid]/status file.

pub fn stat(&self) -> ProcResult<Stat>

Returns the status info from /proc/[pid]/stat.

pub fn loginuid(&self) -> ProcResult<u32>

Gets the process’ login uid. May not be available.

pub fn oom_score(&self) -> ProcResult<u32>

The current score that the kernel gives to this process for the purpose of selecting a process for the OOM-killer

A higher score means that the process is more likely to be selected by the OOM-killer. The basis for this score is the amount of memory used by the process, plus other factors.

(Since linux 2.6.11)

pub fn statm(&self) -> ProcResult<StatM>

Set process memory information

Much of this data is the same as the data from stat() and status()

pub fn task_main_thread(&self) -> ProcResult<Task>

Return a task for the main thread of this process

pub fn task_from_tid(&self, tid: i32) -> ProcResult<Task>

Return a task for the main thread of this process

pub fn schedstat(&self) -> ProcResult<Schedstat>

Return the Schedstat for this process, based on the /proc/<pid>/schedstat file.

(Requires CONFIG_SCHED_INFO)

pub fn tasks(&self) -> ProcResult<TasksIter>

Iterate over all the Tasks (aka Threads) in this process

Note that the iterator does not receive a snapshot of tasks, it is a lazy iterator over whatever happens to be running when the iterator gets there, see the examples below.

Examples

Simple iteration over subtasks

If you want to get the info that most closely matches what was running when you call tasks you should collect them as quikcly as possible, and then run processing over that collection:

let name = "testing:example";
let t = thread::Builder::new().name(name.to_string())
  .spawn(move || { // do work
  })?;

let proc = Process::myself()?;

// Collect a snapshot
let threads: Vec<_> = proc.tasks()?.flatten().map(|t| t.stat().unwrap().comm).collect();
threads.iter().find(|s| &**s == name).expect("thread should exist");

The TaskIterator is lazy

This means both that tasks that stop before you get to them in iteration will not be there, and that new tasks that are created after you start the iterator will appear.

let proc = Process::myself()?;

// Task iteration is lazy
let mut task_iter = proc.tasks()?.flatten().map(|t| t.stat().unwrap().comm);

let name = "testing:lazy";
let t = thread::Builder::new().name(name.to_string())
  .spawn(move || { // do work
  })?;

task_iter.find(|s| &**s == name).expect("thread should exist");

Tasks that stop while you’re iterating may or may not appear:

let name = "testing:stopped";
let t = thread::Builder::new().name(name.to_string())
  .spawn(move || { // do work
  })?;

let proc = Process::myself()?;

// Task iteration is lazy
let mut task_iter = proc.tasks()?.flatten().map(|t| t.stat().unwrap().comm);

t.join().unwrap();

// It's impossible to know if this is going to be gone
let _ = task_iter.find(|s| &**s == name).is_some();

pub fn tcp(&self) -> ProcResult<Vec<TcpNetEntry>>

Reads the tcp socket table from the process net namespace

pub fn tcp6(&self) -> ProcResult<Vec<TcpNetEntry>>

Reads the tcp6 socket table from the process net namespace

pub fn udp(&self) -> ProcResult<Vec<UdpNetEntry>>

Reads the udp socket table from the process net namespace

pub fn udp6(&self) -> ProcResult<Vec<UdpNetEntry>>

Reads the udp6 socket table from the process net namespace

pub fn mem(&self) -> ProcResult<File>

Opens a file to the process’s memory (/proc/<pid>/mem).

Note: you cannot start reading from the start of the file. You must first seek to a mapped page. See Process::maps.

Permission to access this file is governed by a ptrace access mode PTRACE_MODE_ATTACH_FSCREDS check

Example

Find the offset of the “hello” string in the process’s stack, and compare it to the pointer of the variable containing “hello”

let me = Process::myself().unwrap();
let mut mem = me.mem().unwrap();
let maps = me.maps().unwrap();

let hello = "hello".to_string();

for map in maps {
    if map.pathname == MMapPath::Heap {
        mem.seek(SeekFrom::Start(map.address.0)).unwrap();
        let mut buf = vec![0; (map.address.1 - map.address.0) as usize];
        mem.read_exact(&mut buf).unwrap();
        let idx = buf.windows(5).position(|p| p == b"hello").unwrap();
        assert_eq!(map.address.0 + idx as u64, hello.as_ptr() as u64);
    }
}

impl Process

pub fn cgroups(&self) -> ProcResult<Vec<ProcessCgroup>>

Describes control groups to which the process with the corresponding PID belongs.

The displayed information differs for cgroupsversion 1 and version 2 hierarchies.

Trait Implementations

impl Debug for Process

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.